Sintering device.



M. McMURRAY & B. J. MULLEN.

SINTERING DEVICE.

APPLICATION FILED mac. 20, 1913.

Patented Jan. 25, 1916.

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MAX MCMURRAY, OF CLEVELAND, AND'BENJ'AMIN J. MULLEN, OF LEETONIA, OHIO;SAID MULLEN ASSIGNOR TO UNITED IRON AND STEEL COMPANY, OF CLEVELAND,OHIO, A CORPORATION OF PENNSYLVANIA.

SINTERING DEVICE.

Original application filed October 14, 1913, Serial No. 795,143.

Specification of Letters Patent.

20, 1913. Serial No. 307,932.

To all whom it may concern:

Be it known that we, MAX MC-MURRAY and BENJAMIN J. MULLEN, citizens ofthe United States, residents, respectively, of Cleveland, county ofCuyahoga, and State of Ohio, and Lcetonia, county of Columbiana, andState of Ohio, have invented a new and useful Improvement in SinteringDevices, of which the following is a specification, the principle of theinvention being herein explained and the best mode in which we havecontemplated applying that principle, so as to distinguish it from otherinventions.

Our invention relates to sintering pans used for the purpose ofsintcring or agglomerating pulverulent material or ores, such as forinstance, flue dust from blast furnaces.

The subject-matter of this application constitutes a division of ourapplication I 795,1-i3, filed October 1a, 1913 for grate-bars.

One well-known method of sintering involves the use of a receptaclecomprising a main or body portion forming the sides and ends, togetherwith a bottom structure composed of grate-bars perforated uniformlythroughout *ith slots parallel with each other and running atright-anglesto the axis of the bar. Upon this there is laid a layer ofmaterial forming a porous hearth of a character such as will prevent thepulverulent material from passing through said perforations. The chargeof pulverulent material is then laid upon the porous hearth, air passedthrough it from the top downward and thechargeignited. After ignitionthe passage of air is continued and the sintering process thus carriedout and completed, all as is well-known to those skilled in the art. Wehave found, however, that the use of a sintering pan of usual andabove-described construction in said process, produces a resultantmaterial which is not uniform in character. That is, we have found thatthe sintering process is not carried out uniformly throughout the massand that that portion of the charge adjacent to and extending asubstantial distance inwardly from the sides and ends is subjected to aless active sintering operation, than is the remainder of the charge.

Heretofore it has been customary to utilize a multiplicity of grate-barsof the above described character, each of which was pro vid'ed with thesame number and size of perforations or slots similarly located, so thatall of the bars were equally permeable and the degree of permeabilitywas the same throughout all of the operative portions of each bar. Suchconstruction of bars, we have found, permitted the air to short-circuitalong the side and end walls of the pan and prevented the air frompassing through that portion of the charge contiguous to said sides andends for a substantial distance inwardly, in the'amount necessary toproduce uniform sintering throughout the entire charge. In other wordsthe air did not pass through all of the charge at the same rate, thusobviously producing a product non-uniform in character.

The object of our invention, therefore, is to provide a sinteringapparatus by means of which the sintering process may be carried outuniformly throughout the entire charge and a consequent uniformity ofthe resultant product thus obtained. The desirability of obtaining suchuniformity is readily apparent and understood by those skilled in theart.

lVith the said object in view, our invention consists of meanshereinafter fully described and particularly setforth in the claims.

The annexed drawlng and the following description set forth in detailcertain means embodying our invention, the disclosed means, however,constituting but one of various mechanical forms in which the principleof the invention may be employed.

In said annexed drawing: Figure l is a plan of a sinteringp-an embodyingour invention. Fig. 2 is a longitudinal central section of same. Fig. 3is a fragmentary side elevation showing the grate-bars forming a part ofthe said pan. Fig. at is a fragmentary plan of such bar. Fig. 5 is avertical transverse section of a bar. Fig. 6 is a fragmentary plan of amodified form of bar and Fig. 7 is a similar view of a secondmodification.

In the illustrated embodiment of our in vention, A is the main or bodyportion of a well-known type of sintering pan, forming the ends andsides of the latter. Se-

cured in any suitable manner and forming a bottom structure is a seriesof grate-bars B of suitable width, all of which, excepting the end barsB B, are provided with a multiplicity of equidistant circularperforations which occupy the major portion of each bar, a substantialportion of each end, however, being left blank, as shown in Figs. 1 and4. Below these bars is the exhaust chamber C, having the outlets 0 c,which may be connected with suitable exhausting apparatus. As in thepreviously-known apparatus, a layer of suitable material D, such aslimestone screenings, is placed upon the bars and forms the poroushearth for the charge E. The two end bars B B are left completely blank.In a pan having inside dimensions of twelve by seven feet, these barsare about 12% inches in width at the ends and the distance from suchends to the center-lines of the nearest row of perforations is also madeabout 12% inches. Viewed from below, then, the perforated portion of thebottom structure will be seen to be surrounded by an imperforaterectangular annulus about 12 inches in width. The effect of thisimperforate portion is to modify the course of the air in so far asrelates to the outside portion of the charge, so as to cause such air topass through this part of the charge at substantially the same rate asthat at which it passes through every otherpart of the charge. While weprefer to use circular perforations, slots may be employed, as shown, inFig. 7, in which event the length of the blank portion may be madesubstantially the same as in the case of the circular perforations,provided the area of each slot is substantially equal to the area of onetransverse row of circular perforations.

The above-described construction of the bars may be modified in thecircular-perforation construction, by decreasing the length of the blankportions and introducing a lesserv number of circular perforationsbetween such blank portions and the normally perforated portion, asshown in Fig. 6. When slots are used, a similar modification may beresorted to, smaller slots be ing used as shown in Fig. 7.

In any of the above-described vconstructions of our improved bar, a baris provided which has a varying degree of permeability throughout itsoperative portions, that is, that portion exposed in the exhaustchamber, a substantial part of each end being imperforate. In thefirst-described bar the permeability varies from zero throughout oneportion thereof, to a maximum throughout the remainder. In the modifiedconstruction, it varies from zero at the end to the normal, with anintermediate part having an intermediate degree of permeability. Thisbeing the case, the entire bottom structure is arranged to have avarying permeability. l/Vhile slots instead of circular perforations maybe employed, as above noted, we have found the circular perforations tobe preferable.

Having fully described our invention, What we claim and desire to secureby Letters Patent is 1- 1. A sintering pan comprising the combinationwith the main or body portion forming the ends and sides; of a bottomstructure composed of perforated gratebars; a substantial portion ofsaid bottom structure contiguous to said ends and sides beingimperforate, and extending a distance from the sides or ends of said pansubstantially greater than the imperforate distance between theindividual grate bars.

2. In a sintering pan, the combination with a main or body portionforming the ends and sides; of a bottom structure composed of perforatedgrate bars; a substantial portion of such bottom structure contiguous tosaid ends and sides and exposed to the space beneath said bottomstructure, being imperforate, and extending a distance from the sides orends of said pan substantially greater than the imperforate distance between the individual grate bars.

Signed by me, this 6th day of December,

4 MAX MGMURRAY. Attested by D. K. Row, K. L. SISUNG. Signed by me, this3 day of December,

1913. BENJAMIN J. MULLEN. Attested by N. E. WARREN, C. J. SULLIVAN.

Copies of this patent may be obtained for five cents each, by addressingthe Commissioner of Patents,

Washington, D. G.

